scholarly journals Relay cross metathesis reactions of vinylphosphonates

2014 ◽  
Vol 10 ◽  
pp. 1933-1941 ◽  
Author(s):  
Raj K Malla ◽  
Jeremy N Ridenour ◽  
Christopher D Spilling
Keyword(s):  
Reaction Mechanism ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Cross Metathesis ◽  
Metathesis Reactions ◽  
Terminal Alkenes ◽  
The Cross

Dimethyl (β-substituted) vinylphosphonates do not readily undergo cross metathesis reactions with Grubbs catalyst and terminal alkenes. However, the corresponding mono- or diallyl vinylphosphonate esters undergo facile cross metathesis reactions. The improved reactivity is attributed to a relay step in the cross metathesis reaction mechanism.

scholarly journals Cross-metathesis reaction of α- and β-vinyl C-glycosides with alkenes

2015 ◽  
Vol 11 ◽  
pp. 1392-1397 ◽  
Author(s):  
Ivan Šnajdr ◽  
Kamil Parkan ◽  
Filip Hessler ◽  
Martin Kotora
Keyword(s):  
Metathesis Reaction ◽  
Simple Method ◽  
Cross Metathesis ◽  
Terminal Alkenes ◽  
The Cross

Cross-metathesis of α- and β-vinyl C-deoxyribosides and α-vinyl C-galactoside with various terminal alkenes under different conditions was studied. The cross-metathesis of the former proceeded with good yields of the corresponding products in ClCH2CH2Cl the latter required the presence of CuI in CH2Cl2 to achieve good yields of the products. A simple method for the preparation of α- and β-vinyl C-deoxyribosides was also developed. In addition, feasibility of deprotection and further transformations were briefly explored.

Study of the Cross-Metathesis Reaction of α-Hydroxy β,γ-Unsaturated Amides towards a Rapid and Flexible Total ­Synthesis of Symbioramide and its Isomer

Synlett ◽  
2017 ◽  
Vol 29 (02) ◽  
pp. 230-234 ◽  
Author(s):  
Alexandre Gratais ◽  
Samir Bouzbouz
Keyword(s):  
Methyl Ester ◽  
Total Synthesis ◽  
Metathesis Reaction ◽  
Cross Metathesis ◽  
Metathesis Reactions ◽  
The Cross

The reactivity of novel α-hydroxy β,γ-unsaturated amides in cross-metathesis reactions was extensively studied and used to perform a short total synthesis of symbioramide and its isomer from ­l-serine methyl ester.

Complete Stereocontrol in the Synthesis of Harmonine and Novel Analogues Facilitated by a Grubbs Z-Selective Cross-Metathesis Catalyst

2015 ◽  
Vol 68 (12) ◽  
pp. 1815 ◽  
Author(s):  
Steven-Alan G. Abel ◽  
Wesley J. Olivier ◽  
Richard L. Pederson ◽  
Alex C. Bissember ◽  
Jason A. Smith
Keyword(s):  
The Self ◽  
Metathesis Reaction ◽  
Cross Metathesis ◽  
Metathesis Catalyst ◽  
The Cross

(R)-Harmonine was synthesised in 15 % overall yield via a six-step sequence exploiting a Z-selective cross-metathesis reaction as its centrepiece. By this strategy, the cis-olefin present in the target could be installed exclusively. The use of an alcohol and an ester as the amine precursors was crucial for isolating the cross-metathesis product from the self-metathesis products. This method was also used to prepare two novel analogues of harmonine.

Regulation of the degree of blockiness of the norbornene–cyclooctene copolymer synthesized via the cross-metathesis reaction

2016 ◽  
Vol 58 (3) ◽  
pp. 292-297 ◽  
Author(s):  
Yu. I. Denisova ◽  
M. L. Gringolts ◽  
L. B. Krentsel’ ◽  
G. A. Shandryuk ◽  
A. D. Litmanovich ◽  
...  
Keyword(s):  
Metathesis Reaction ◽  
Cross Metathesis ◽  
The Cross

A facile new procedure for the deprotection of allyl ethers under mild conditions

2000 ◽  
Vol 78 (6) ◽  
pp. 838-845 ◽  
Author(s):  
Yun-Jin Hu ◽  
Romyr Dominique ◽  
Sanjoy Kumar Das ◽  
René Roy
Keyword(s):  
Key Words ◽  
Catalytic System ◽  
Olefin Metathesis ◽  
Allyl Ether ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Allyl Ethers ◽  
Mild Conditions ◽  
Cross Metathesis ◽  
Allylic Ethers

A novel isomerization of O-allyl glycosides into prop-1-enyl glycosides was observed instead of cross-metathesis during an olefin metathesis reaction using Grubbs' ruthenium benzylidene catalyst (Cy3P)2RuCl2=CHPh (1), N-allyltritylamine, and N,N-diisopropylethylamine as necessary auxiliary reagents. In the search for a better catalytic system, it has been found that dichlorotris(triphenylphosphine)ruthenium(II), [(C6H5)3P]3RuCl2, (2) was much more efficient for the isomerization of allylic ethers. The labile prop-1-enyl group was easily hydrolyzed using HgCl2-HgO and the hemiacetals (25-32) were isolated in excellent yields (ca. 90%).Key words: allyl ether, carbohydrate, Grubbs' catalyst, isomerization, metathesis, deprotection.

scholarly journals Designing liquid-crystalline gold nanoparticles via the olefin cross-metathesis reaction

2016 ◽  
Vol 20 (08n11) ◽  
pp. 1060-1064 ◽  
Author(s):  
Thanh Tung Nguyen ◽  
Thi Le Anh Nguyen ◽  
Robert Deschenaux
Keyword(s):  
Gold Nanoparticles ◽  
Liquid Crystalline ◽  
Second Generation ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Terminal Olefin ◽  
Organic Shell ◽  
Smectic A ◽  
Cross Metathesis ◽  
Liquid Crystalline Nanoparticles

Liquid-crystalline gold nanoparticles were prepared by grafting mesomorphic [Formula: see text],[Formula: see text]-unsaturated carbonyl olefins onto the organic shell of gold nanoparticles containing terminal olefin ligands by applying the olefin cross-metathesis. The latter reaction was performed under standard conditions using second-generation Grubbs catalyst. The title materials were found to be stable up to 200[Formula: see text] C and gave rise to the formation of smectic A phases in agreement with the structure and nature of the liquid-crystalline promoters. The olefin cross-metathesis proved to be a reaction of choice for the design of liquid-crystalline nanoparticles.

Ruthenium-catalyzed cross-metathesis with electron-rich phenyl vinyl sulfide enables access to 2,3-dideoxy-d-ribopyranose ring system donors

RSC Advances ◽  
2014 ◽  
Vol 4 (38) ◽  
pp. 19794-19799 ◽  
Author(s):  
Omar Boutureira ◽  
M. Isabel Matheu ◽  
Yolanda Díaz ◽  
Sergio Castillón
Keyword(s):  
Microwave Irradiation ◽  
Ring System ◽  
Metathesis Reaction ◽  
Vinyl Sulfide ◽  
Cross Metathesis ◽  
The Cross ◽  
Flexible Metal ◽  
Phenyl Vinyl

Microwave irradiation effectively accelerates the cross-metathesis reaction of 2-deoxy-d-ribose hydroxyalkene and derivatives with electron-rich phenyl vinyl sulfide using commercially available ruthenium-based catalysts, thus providing a flexible metal-mediated route to 2,3-dideoxy-d-ribopyranose ring system donors.

scholarly journals Recent Advances in Total Synthesis via Metathesis Reactions

Synthesis ◽  
2018 ◽  
Vol 50 (19) ◽  
pp. 3749-3786 ◽  
Author(s):  
Francisco Sarabia ◽  
Iván Cheng-Sánchez
Keyword(s):  
Total Synthesis ◽  
Tandem Reactions ◽  
Alkyne Metathesis ◽  
Enyne Metathesis ◽  
Metathesis Reaction ◽  
Ring Closing Metathesis ◽  
Total Syntheses ◽  
Cross Metathesis ◽  
Carbon Carbon Bonds ◽  
Metathesis Reactions

The metathesis reactions, in their various versions, have become a powerful and extremely valuable tool for the formation of carbon–carbon bonds in organic synthesis. The plethora of available catalysts to perform these reactions, combined with the various transformations that can be accomplished, have positioned the metathesis processes as one of the most important reactions of this century. In this review, we highlight the most relevant synthetic contributions published between 2012 and early 2018 in the field of total synthesis, reflecting the state of the art of this chemistry and demonstrating the significant synthetic potential of these methodologies.1 Introduction2 Alkene Metathesis in Total Synthesis2.1 Total Synthesis Based on a Ring-Closing-Metathesis Reaction2.2 Total Synthesis Based on a Cross-Metathesis Reaction2.3 Strategies for Selective and Efficient Metathesis Reactions of Alkenes2.3.1 Temporary Tethered Ring-Closing Metathesis2.3.2 Relay Ring-Closing Metathesis2.3.3 Stereoselective Alkene Metathesis2.3.4 Alkene Metathesis in Tandem Reactions3 Enyne Metathesis in Total Synthesis3.1 Total Syntheses Based on a Ring-Closing Enyne-Metathesis Reaction3.2 Total Syntheses Based on an Enyne Cross-Metathesis Reaction3.3 Enyne Metathesis in Tandem Reactions4 Alkyne Metathesis in Total Synthesis4.1 Total Synthesis Based on a Ring-Closing Alkyne-Metathesis Reaction4.2 Other Types of Alkyne-Metathesis Reactions5 Conclusions

Synthesis of Unsaturated Esters by Cross-Metathesis of Terpenes and Natural Rubber Using Ru-Alkylidene Catalysts

2019 ◽  
Vol 23 (12) ◽  
pp. 1356-1364
Author(s):  
Araceli Martínez ◽  
Mikhail A. Tlenkopatchev ◽  
Selena Gutiérrez ◽  
Manuel Burelo ◽  
Joel Vargas ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Unsaturated Ester ◽  
Low Molecular Weight ◽  
Diethyl Maleate ◽  
Metathesis Reaction ◽  
Unsaturated Esters ◽  
Cross Metathesis ◽  
Dimethyl Maleate ◽  
The Cross ◽  
Low Activity

This study reports the cross-metathesis of bicyclic β-pinene, acyclic cis-3- methylpent-2-ene terpenes and the natural rubber with functionalized olefins, a route for the functionalization of the carbon-carbon double bond of natural products to obtain aliphatic unsaturated esters. The production of unsaturated esters from β-pinene and cis-3- methylpent-2-ene via cross-metathesis reaction with dimethyl maleate and diethyl maleate in the presence of the ruthenium-alkylidene [Ru(Cl)2(=CHPh)(1,3-bis(2,4,6- trimethylphenyl)-2-imidazolidinylidene)(PCy3)] (I), [Ru(Cl)2(=CH(o-isopropoxyphenylmethylene))( 1,3-bis(2,4,6-trimethylphenyl) -2-imidazolidinylidene)] (II) and rutheniumvinylidene [RuCl2(=C=CH(p-C6H4CF3))(PCy3)2] (III) was carried out. Results showed that the reaction of β-pinene with diethyl maleate using II catalyst produced unsaturated esters with 43 % selectivity. I and III catalysts showed low activity toward the cross-metathesis of β-pinene and dimethyl maleate. A survey about the cross-metathesis of acyclic cis-3-methylpent-2-ene with diethyl maleate by II catalyst was also studied. The formation of ethyl but-2-enoate and ethyl-3-methylpent-2-enoate products was highly selective by 63 %. The unsaturated esters formation from the cross-metathesis degradation of natural rubber (99.9 % cis-polyisoprene) with dimethyl maleate and diethyl maleate using I-III catalysts was accomplished as well. I and II catalysts showed high activity in the degradation of natural rubber with diethyl maleate to produce the low molecular weight of oligomers unsaturated ester products (Mn = 1 x 103 g mol-1) with isoprene units of m = 10 – 27 and yields ranging from 68 to 94 %.

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